Constant potential device



8, 1931. A. JAUMANN 1,819,604

CONSTANT POTENTIAL DEVICE Filed Feb. 27. 1929 I I? 45 v 02 49 {Inventor@51 14 5 Gamma 1 fl Patented Aug. 18, 1931 UNITED\S\TATES PATENT OFFICEANDREAS JAUMANN, or imatm-crmatorrnnnnne, GERMANY, assrenoa r snnmns &HALSKE, nxrmnensnusomrr, or smunnss'rm, NEAR BERLIN, ennmmr,

A CORPORATION OF GERMANY CONSTANT rornn'rmr. nnvrcn Application filedFebruary 27; 1929, Serial No.

' For the smoothing of current. supplied from direct current generators,rectifie'rs and similar sources of current which fail to fur.- nish apure direct current, but rather a kind of direct current having, forinstance, al-

ternating current components superposed thereon, the use of athermionic-tube has been suggested whose internal resistance is soinfluenced by the source "of current that the potential fluctuations areeliminated. Along the line of this suggestion action is broughtparticularly by the fall of potential across a resistance whichinfluences the grid of the tube. However, through the control resistancethere flows also the consuming or load current so that the suppressionof the potentialfluctuations is not insured in a perfect manner. owingto the de- "pendence on the load current. According to the invention,the disturbances are eliminated independently of the load current, andfor this purposethe control resistance is connected in a circuit inparallel relationship to the} consumer apparatus. Also the tubearrangement is pref." c in erably included in this parallel bran series.with the control resistance. The fall of potential in the latter mayinfluence the tube arrangement in various ways, as will be seen from thefollowing specification when read in connection with the accompanyingdrawings in which Figure 1 shows thecircuit arrangement of a constantpotential device constructed in accordance withmy invention; whileFigures 1A, 2 and 3 show modifications of the device of Figure 1. 1

Referring to the drawings, Figures. 1 and 1A show a simple arrangementin which the control resistance R is associated with the positive poleof the source of current and with' the plate of thermionic tube A. Thefilament circuit of this tube is united with the negative pole of thesource. In parallel relation with the resistance R is the primarywinding of a transformer whose secondary windin is included in the gridcircuit of the tube. s a rule, a negative biasing potential is requiredat the grid in order to insure proper operation of t e scheme, saidbiasinadequate.

should-be rather large. -The fa 342, 91, and in Germany February 17, ms.

ing potential being furnished from a battery 3. As the current throughows there is produced a grid potential, we the result that the platepotential of the tube is varied. -If the ratio of the transformer isproperly chosen, the variation in the plate potential will justcompensate the variation of the fall of potential across resistance B,so that the potential"acrossrterminals 1, 2, with which the loadresistance, for instance, the plate circuit of tube arrangement isconnected, preserves a constant value. In order that the superposedalternating current components may be properly suppressed, it will bedesirable in manyinstances to keep the direct current magnetization inthe transformer as low as possible. For this urpose may be employed athird winding on the transformer,.as shown in Fi re 1, one end of whichis associated wit .the primary winding and is brought by way ofresistance" 'r to the negative p0 e. a v

This circuitscheme operates properly in- .side a frequency range whichdepends upon the properties of the transformer. As a general rule, inthe presence of very low and very high frequencies, compensation will beIn this respect the scheme shown in Figure 2 operates more favorably.

Also in this arrangement, a control resistanceRl-and-a thermionic tube Aare disposed in series between the terminals of the source of current.In parallel relation to the .tube A is an auxiliary tube B in serieswith a resistance R2 which, as a 1general rule, of potential acrossresistance R1 directly controls .the

grid of tube B which, under certain circumstances may be with thenegative pole; of the source of current. At the plate of this tube Barise potential variations of opposite si and larger amplitude, andthese are fed t rou h a grid battery to the grid of the main tu e A. If,then,*the current through the first tube grows and as a consequence thefall of otential' across resistance R1, this is attende with a decreaseof otential at the grid of the auxiliar tube. f the value of resistanceR2 is consi erable (which it preferably should be) the plate current inm tube B does not change substantially, and there occurs a considerablygreater positive potential variation at the plate of B and consequentlyalso at the grid of tube A. This potential variation may be so chosenthat the potential at terminals 1, 2, for the load resistance remainsconstant.

The auxiliary tube serves essentially for electrostatic control and maytherefore be ordinarily quite small. The arrangement moreover, ispredicated for its operation only on ohmic resistances so that it ispractically independent of frequency.

Since the circuit arrangements hereinbefore disclosed maintain a directcurrent potential across their terminals, while alternating currentpotentials or rapid fluctuations of potential of appreciable size areprecluded, they act similarly as a very large condenser so that theycould also be used in conjunction with choke-coils or low-pass filtersfor filtering out alternating current components.

A scheme of this kind is illustrated in Figure 3, connected with thepositive terminal of the source is a choke-coil D followed by a circuitarrangement which essentially is similar to the one shown in Figure 2.In lieu of the biasing potential battery between the plate of tube B andthe grid of tube A there is used here a condenser, and the grid of tubeA is associated with the negative terminal of the source by way of aresistance W. The grid of tube B is united with a point of controlresistance R1, and then the biasing potential battery in the gridcircuit of tube B may be dispensable.

The operation of the tube scheme shown in Figure 3 is fundamentallysimilar to Figure 2. However, what should also be kept in mind is thatthe current flows through choke-coil D to the consumer which is unitedwith terminals 1 and 2. Since the value of this current is not constantor invariable once for ever, the potential will be a function of theload current even if the internal resistance of the source isnegligible, because a fall of potential is set up across the directcurrent resistance of the choke-coil D. However, since the tubearrangement is designed to preserve a constant potential, it willproduce and result in a regulating current such that, in the presence ofvariable load, the fall of potential across the choke-coil remainsconstant. As a result the operation of the tube arrangement may beunfavorably affected. However, it is possible to render it independentof the load by the aid of a compensating resistance 1" which, as ageneral rule, need have only a small value, and which, in the embodimentshown by way of example in Figure 3, may be connected between thecontrol resistance R1 and the grid resistance W.

I claim:

1. An arrangement for smoothing out current to be applied from apulsating direct current source to a load circuit including, athermionic tube having an anode cathode and control electrode, a fixedimpedance, means connecting the impedance of said tube and said fixedimpedance in parallel with said load circuit, coupling means betweensaid fixed impedance and said control electrode and amplifying means insaid coupling means whereby variations in potential in said fixedimpedance due to pulsations in said source are amplified and applied tothe control electrode of said tube.

2. An arrangement for supplying direct current at constant potentialfrom a pulsating direct current source to a load circuit including, athermionic tube having anode cathode and control electrodes, a controlresistance, a circuit connecting the impedance of said tube and saidcontrol resistance in parallel with the load circuit, an auxiliarythermionic tube having an anode, a cathode and a control electrode, acircuit connecting the anode cathode impedance of said last named tubein parallel with the anode cathode impedance of said first named tube,coupling means connected between said resistance and the controlelectrode of said last named tube, means connecting the anode of saidlast named tube to the control electrode of said first named tube, and aresistance connecting the control electrode of said first named tube tothe negative terminal of said source.

3. In apparatus for smoothing out the potential of current obtained froma pulsating direct current source, a circuit including the anode andcathode impedance of a thermionic triode connected across the outputterminals of said source, a series resistance in said circuit, anauxiliary triode, a circuit connecting the anode cathode impedance ofsaid auxiliary tube in parallel to the anode cathode impedance of saidmain tube, a series resistance in said last mentioned circuit, aconnection between the resistance in said first named circuit and thegrid electrode of said auxiliary tube, a connection between the anodeelect-rode of said auxiliary tube and the grid electrode of said maintube, and a condenser in said last named connection.

4. In radio apparatus adapted to supply constant potential from apulsating direct current source to a load circuit connected across theterminals of said source, a circuit including a fixed impedance and avariable impedance connected in series across said source, impedancecontrol means associated with said variable impedance, voltageamplifying means connecting said fixed impedance to said variableimpedance, whereby potential variations in said fixed impedance due topulsations in said source are vamplified and applied to 'said varyingmeans to regulate the impe impedance ance of said arallel circuit.

5. n means for supplying direct current at constant potential from asource of pulsating direct current to a load circuit, a fixed impedance,a thermionic tube having its anode cathode impedance connected in serieswith said fixed impedance across the I termlnals of sald source, atransformer having its primary winding connected in parallel with saidfixed impedance and its secondary winding connected to the controlelectrode of said thermionic tube whereb the potential variations insaid fixed impe ance are amplified and applied to the control electrodeof said tube.

A 6.- Means for sup )lying direct current at constant potential i fixedimpedance and a variable impedance connected in series across theterminals of said source, impedance control means associated with saidvariable impedance, a trans-- former having its primary windingconnected in parallel with said fixed impedance and its secondarywinding connected with said impedance control -means,'whereby potentialvariations insaid fixed impedance, due to pulsations in said source, areamplified and applied to said impedance control means.

7 An arrangement, as claimed in claim 6, in which said transformer has athird winding connected in parallel with said variable impedance.

8. In means for su plying direct current at constant potential rom apulsating direct current source to a load circuit, a circuit includingthe anode and cathode impedance ofa thermionic triode connected acrossthe output terminals of said source, an impedance in series with saidcircuit, an auxiliary triode having its anode cathode impedanceconnected through a series impedance in parallel with the anode cathodeimpedance of said first named tube, means for connecting the controlelectrode cathode impedance of said last named tube in parallel with theand a source of series impedance of said first named circuit anode ofsaid am iary tube to the control electrodeof said first named tube.

ANDREAS JAUMANN.

rom a pulsating direct. current source to a load clrcult including aotential connecting the'

